Hand tool for crimping electrical connectors



Dec. 27, 1966 HAND TOOL FOR Filed April 15, 1959 w. F. BROSKE 3,293,732

CRIMPING ELECTRICAL CONNECTORS 2 Sheets-Sheet 1 INVENTOR. Wuuan F ERosm-z Dec. 27, 1966 w. F. BROSKE 3,293,732

HAND TOOL FOR CRIMPING ELECTRICAL CONNECTORS Filed April 13, 1959 2 Sheets-Sheet 2 INVENTOR. Wuuam E DRosm:

United States Patent 3,293,732 HAND TOOL FOR CRIMPING ELECTRICAL CONNECTORS William F. Broske, Camp Hill, Pa., assignor to AMP Incorporated, Harrisburg, Pa. Filed Apr. 13, 1959, Ser. No. 806,093 16 Claims. (Cl. 29-155.5)

This application constitutes a continuation-in-part of my prior application, Serial No. 793,814, filed February 17, 1959, now Patent No. 3,007,409.

This invention relates to hand tools for crimping connectors onto conductors to form an efficient electrical connection.

It is an object of this invention to provide means for forming a connection whereby the connection can be made quickly and easily. Such connections including very large sizes may be made without the use of heavy equipment or additional sources of power.

The means for making the connection includes connector crimping dies which are contained in a hand tool and operated by an explosive charge also contained in the tool. Additionally, the cartridge providing the charge can only be fired internally, thus reducing the noise level of the report as well as preventing accidental firing of the cartridge. (The term internally-fired refers to a cartridge having the priming means seated within the cartridge at a location remote from the outer surface.)

Furthermore it is an object of this invention to provide a firing device for such a cartridge so that the die will not be acutated unless it is in proper position relative to the connector and the firing cap is properly aligned.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to he understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration in order that others skilled in the art may fully understand the invention ancl the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as .may be best suited to the conditions of a particular use.

In the drawings:

FIGURE 1 is a plan view of a device illustrating a preferred embodiment of the invention;

FIGURE 2 is a sectional view similar to FIGURE 1;

FIGURE 3 is a perspective view of the device shown in FIGURES 1 and 2;

FIGURES 46 are fragmentary views illustrating the cartridge and detonating means during various stages of operation; and

FIGURES 7 and 8 are fragmentary views of the safety device adapted to revent accidental firing.

The tool illustrated in the drawings includes a C-shaped frame 50 with a handle 52 attached thereto to simulate a pistol-grip type of hand tool. The frame has a fixed die 54 secured at one end within the frame 50 and an opposed movable die 56 slidab'le therein. A rod 58 secured to the movable die at one end and having a detonating pin 59 at the other end slides in an opening 60 in the other end of the frame.

A cartridge holding sleeve 62 is secured to the frame coaxially of the opening 60. This sleeve may be integral with the frame. However, by making it separable, it may be made of stronger metal. A cartridge 110 is seated within the sleeve 62 so that the rod 58 moves longitudinally therein. A cap 64 is secured to the out-er end of the sleeve 62 (e.g. by mutilated threads) to firmly retain the 3,293,732 Patented Dec. 27, 1966 ice cartridge within the sleeve. A keyway 66 is disposed along one side of the cap 64 and mates with a keyway 68 on one side of the frame for a purpose described below.

The firing mechanism includes a Y-shaped trigger having a 'base 70 which mates with the handle 52 and a pair of arms 72 and 74. The trigger is pivoted to the frame by a pivot pin 76 and a leaf spring 78 urges it forwardly. The tip of the arm 72 extends into a recess 80 in the movable die 56 when the tool is in the cocked position. The other arm 74 has a spline 82 at its extreme end which fits into the keyway 66, 68. Thus the trigger cannot be actuated until the cap 64 is completely threaded onto the sleeve 62. Orientation of the keyway 66 and 68 occurs when the threading of the cap is completed.

A safety feature includes a pin 84 which extends through an elliptical recess 86 in the body and trigger (see FIGURES 7 and 8). The pin may have a button 88, a shank 90 of lesser diameter than the minor diameter of the recess 86, and a plug 92 of substantially the same diameter as the minor diameter of the recess 86. A spring 94 urges the pin outwardly and a collar 96 limits the outward travel of the pin to the position shown in FIGURE 7 with a plug 92 preventing movement of the trigger 70. Actuation of the pin to the position shown in FIGURE 8 permits operation of the trigger about shank 90. Thus the trigger cannot be inadvertently ope-rated but requires prior positive actuation of the safety device.

As shown in the drawings, FIGURES 4-6, the cartridge consists of a cylinder closed at one end 112 and having a rim 113 for seating the cartridge in the detonating sleeve. In the preferred embodiment the cartridge may 'be made of a molded plastic, e.g. polyethylene. Positioned within the cartridge cylinder 110 by an interference fit is a plug 114. The plug is disposed from the closed end 112 of the cylinder 110 to form a closed space 116 therewith. A quantity of explosive powder 118 is retained in the space 116.

The plug 114 may also be of plastic, in the same manner as the casing. A passageway 120 extends longitudinally through the plug so that its inner end communicates with the powder charge 118. The outer end of the plug 114 contains a recess 122 which is concentric with the passageway 120. The recess 122 retains a primer 124. The plug may be dome-shaped on its inner surface and have a circular recess 126 about its intermediate periphery. This recess functions as a gas check and traps gasses which tend to escape. The cartridge is considered internally fired since the primer can only be detonated by a device internally inserted into the shell.

When it is desired to use the cartridge (e.g. in a tool such as identified above), it is seated therein by rim 113 with the primer detonating means extending into the open end of the casing 110. The cartridge is acutated by the detonating means operating on the primer 124 in the direction of the arrow shown in FIGURE 4.

The explosion of the primer in turn ignites the powder charge 118. Since the cartridge is confined in the tool,

the explosive force drives the plug toward the free end of the cartridge. Thus, because of the inaccessibility of the primer, the cartridge cannot be detonated accidentally, cg. by dropping it or inadvertently striking it. It can only be discharged by inserting a detonating means in the free end of the cartridge and delivering energy to the rection of thrust. Thus,,there is no possibility of escape gases leaking out through the back of the cartridge, as is possible in cartridges having a primer seated in the exterior wall.

The movable die 56 also has aflixed thereto a pin 140 which supports one end of a coil spring 142. The opposite end of the spring is attached to a similar pin 144 affixed to the frame. The spring normally holds the die in retracted position. (Two sets of springs, pins, etc. may be employed to give the assembly more balance.)

A second handle 146 may be added to the front of the tool to provide a better grasp. Also the cap 64 may be attached to the frame by means of a chain 148 and ring 150 so that the cap wil not become separated and perhaps lost. The ring 150 is rotatable relative to the cap 64 to prevent the chain from becoming twisted when the cap 64 is threaded to the sleeve 62.

Operation A connector C is inserted into the fixed die 54 and the movable die 56 is moved toward the fixed die against the action of springs 142 so that the arm 72 is moved into the recess 80 to cock the tool. When the tool is cocked the safety pin 88, etc., locks it in position. A conductor W is inserted into the connector and a cartridge 110 is fitted into the sleeve 62. The cap 64 is threaded onto the sleeve 64 to support the cartridge 110 during the detonating cycle. Alignment of keyway 66 and 68 insures that the cap is on tightly.

One hand grips the handle 52 while the other hand grips the handle 146, and using it as leverage the pin 84 is depressed against the action of spring 94 to arm the tool.

With the tool loaded, cocked and armed, squeezing the base of the trigger 70 against the action of spring 78 causes the arm 72 to be released from the slot 80, while spline 82 enters the keyway 66, 68. Since the spline is only free to move when the cap is fully tightened premature firing is prevented.

Releasing the arm 72 from the slot 80 permits springs 142 to drive the rod 58 and and detonating pin 59 against the primer 124 (FIGURES 4-6). The primer ignites the powder charge 118 to drive the plug 114, rod 58, and die 56 toward the fixed die 54 and thus etfecting a crimped connection of connector C and conductor W. The mating of the dies 54 and 56 limit their travel so that the plug 114 is fused within the cartridge 110 to contain the explosive gases in the closed chamber of the cartridge.

The degree of constriction of the ferrule is a function of the distance between the detonating end of the ram 58 and the powder charge 118 at the time of detonation. That is, the further the ram is spaced from the detonating substance, the lesser the degree of crimping. The internal firing mechanism, whereby the charge is detonated by one end of the ram, insures the maximum crimping, since the detonating end of the ram must be in contact with the plug 114 before the device will fire. Additionally the mechanism has the advantages of preventing inadvertent firing of the cartridge as well as limiting the noise of the report.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

I claim:

1. The method of exploding a cartridge having a hollow bore therein, which includes a primer located centrally of the cartridge including the steps of providing a die means with a rod secured to the non-working surface, securing the cartridge in place so that the bore is aligned with a workpiece, driving the rod into the cartridge to detonate the cartridge and then permitting the die means to be actuated by the explosive charge toward the workpiece.

2. The method of crimping an electrical connector to a conductor, including the steps of: (1) placing the connector with the conductor therein between cooperative relatively movable dies; (2) detonating an explosive charge by driving at least one of the dies toward the explosive charge; and (3) causing the force generated by the explosive charge to actuate the dies relative to each other, thereby bringing the actuated dies into cooperation to crimp the connector therebetween.

3. A tool of the character described including dies operable into and out of crimping position, said tool adapted to receive an explosive charge, and means on one of said dies for detonating said explosive charge.

4. The tool of claim 3 wherein the explosive charge is contained in a cartridge, and the means for detonating the explosive charge includes a rod secured to one of the dies, detonating means on one end of the rod whereby at least one end of the rod may be driven into the barrel of a cartridge having a priming means within the barrel, and means for driving the rod into the cartridge to detonate the charge and permitting the rod to be actuated by the charge so the dies are brought into cooperative relationship.

5. A tool of the character described including a base member, a first die on the base member, a second die on the base member movable toward and away from the first die, a cartridge adapted to be internally fired seated in the base member, a rod having one end secured to the second die, the other end of said rod containing a detonating means for detonating the explosive charge, and primer means in said cartridge for causing said detonating means to ignite the charge.

6. The tool of claim 5 including means for locking the firing means against inadvertent actuation.

7. The tool of claim 5 including spring means normally urging the detonating means in a direction toward the explosive means whereby the spring means may be stretched and released to drive the detonating means against the explosive means.

8. The tool of claim 7 including a releasable trigger means for holding the spring means in extended position.

9. The tool of claim 8 including releasable means for locking the trigger When the spring means is in extended position.

10. The combination of a tool and cartridge for crimping electrical connectors including a body member, a first die on said body member, a second die on said body memher, said dies being relatively movable into and out of cooperation with each other, means forrelatively actuating said dies including a cartridge seated in the tool, said cartridge open at one end and closed at the other end, an explosive powder charge in said cartridge, a plug in said cartridge to retain the powder charge in the cartridge, a priming means in the plug, and means in said tool for detonating said primer to detonate the powder.

11. The device of claim 10 wherein the means for detonating the primer includes a rod secured to one of the dies, a free end of said rod disposed in the cartridge, and means for driving the rod against the primer with a force sufficient to detonate the primer.

12. The device of claim 10 including releasable means for locking the detonating means against inadvertent actuation.

13. The device of claim 10 including means for preventing firing unless the cartridge is properly seated and held in place.

14. A device of the character described including, a first and second die relatively actuatable toward and away from each other, means containing said dies permitting them to move into and out of crimping engagement, means for actuating said dies including an explosive means which is adapted to be internally fired, and means on one of said dies for detonating said explosive means.

15. A device for accomplishing useful work including a base member, means thereon for accomplishing work,

explosive means seated in said base member, said explosive means having a primer located in an internal section of said explosive means, firing means on said base member adapted to extend into the internal section and explode the priming means thereby firing said explosive means, whereby the explosive charge is employed to actuate the means for accomplishing work.

16. A device for crimping an electrical connector including a base member, a first die on said base member, a second die on said base member movable towards said first die, explosive means in said base member, said ex plosive means comprising a cartridge closed at one end, an explosive charge in said cartridge, a plug in said cartridge, a priming means in said plug, means on said base member capable of extending into the cartridge to detonate the priming means, and means for actuating the means for detonating the priming means whereby the force of the explosive charge is translated to actuate the dies.

References Cited by the Examiner UNITED STATES PATENTS 138,679 5/1873 Mott et a1 102-46 430,229 6/1890 Garland 102-40 610,305 9/1898 Mino et a1. 29-15555 JOHN F. CAMPBELL, Primary Examiner. NEDWIN BERGER, WHITMORE A. WILTZ,

Examiners.

A. F. ZOBAL, D. L. OTTO, R. W. CHURCH,

Assistant Examiners. 

1. THE METHOD OF EXPLODING A CARTRIDGE HAVING A HOLLOW BORE THEREIN, WHICH INCLUDES A PRIMER LOCATED CENTRALLY OF THE CARTRIDGE INCLUDING THE STEPS OF PROVIDING A DIE MEANS WITH A ROD SECURED TO THE NON-WORKING SURFACE, SECURING THE CARTRIDGE IN PLACE SO THAT THE BORE IS ALIGNED WITH A WORKPIECE, DRIVING THE ROD INTO THE CARTRIDGE TO DETONATE THE CARTRIDGE AND THEN PERMITTING THE DIE MEANS TO BE ACTUATED BY THE EXPLOSIVE CHARGE TOWARD THE WORKPIECE
 3. A TOOL OF THE CHARACTER DESCRIBED INCLUDING DIES OPERABLE INTO AND OUT OF CRIMPING POSITION, SAID TOOL ADAPTED TO RECEIVE AN EXPLOSIVE CHARGE, AND MEANS ON ONE OF SAID DIES FOR DETONATING SAID EXPLOSIVE CHARGE. 